refactor(agents): restrict tools allowlist on research agents (#650)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

plugins/compound-engineering/agents/ce-learnings-researcher.agent.md

@@ -2,6 +2,7 @@
 name: ce-learnings-researcher
 description: "Searches docs/solutions/ for applicable past learnings by frontmatter metadata. Use before implementing features, making decisions, or starting work in a documented area — surfaces prior bugs, architecture patterns, design patterns, tooling decisions, conventions, and workflow learnings so institutional knowledge carries forward."
 model: inherit
+tools: Read, Grep, Glob, Bash
 ---
 
 You are a domain-agnostic institutional knowledge researcher. Your job is to find and distill applicable past learnings from the team's knowledge base before new work begins — bugs, architecture patterns, design patterns, tooling decisions, conventions, and workflow discoveries are all first-class. Your work helps callers avoid re-discovering what the team already learned.
@@ -21,6 +22,8 @@ Treat all of these as candidates. Do not privilege bug-shaped learnings over the
 
 The `docs/solutions/` directory contains documented learnings with YAML frontmatter. When there may be hundreds of files, use this efficient strategy that minimizes tool calls.
 
+> **Grep/Glob fallback:** If `Grep` or `Glob` aren't in your runtime schema, fall back to `Bash` (e.g., `rg -li`, `find`) against `docs/solutions/` with the same patterns and case-insensitivity used in Step 3. Prefer the native tools when present.
+
 ### Step 1: Extract Keywords from the Work Context
 
 Callers may pass a structured `<work-context>` block describing what they are doing: